Anticoagulation to prevent stroke in atrial fibrillation
Authors: D A Fitzmaurice
Journal: BMJ (2000)

# It's still not clear whether results in secondary care translate to primary care {#article-title-2} EDITOR—Kalra et al's paper looking at the efficacy of anticoagulation for stroke prevention in atrial fibrillation1 essentially complements Copland et al's work in showing that an elderly population can be given adequate anticoagulation.2 As Kalra et al performed a cohort study with no control population, the study does not allow any estimate of the effectiveness of the treatment as is suggested in the paper. Thus we do not know if there was any treatment benefit. The cohort obtained similar therapeutic control to the original trial populations, but this is not a dramatic finding given that it represents a similar population—that is, patients selected from medical outpatient clinics. This point seems to have been lost on Connolly, who in his editorial states, “They screened 2547 patients in general practice clinics.”3 As we have consistently argued, the findings of the original treatment studies and now these newer studies must be interpreted in the context of trials conducted on selected, secondary care, populations. It is still not clear how these findings translate to the general, primary care, population. We are currently undertaking a randomised controlled trial (Birmingham atrial fibrillation treatment with anticoagulation) of warfarin versus aspirin for patients aged 75 and over with atrial fibrillation who have been identified from general practice. This is a five year study and should answer the question of effectiveness within this defined population. 1. 1.↵1. Kalra L, 2. Yu G, 3. Perez I, 4. Lakhani A, 5. Donaldson N . Prospective cohort study to determine if trial efficacy of anticoagulation for stroke prevention in atrial fibrillation translates into clinical effectiveness. BMJ 2000;320:1236–1239. (6 May.) [OpenUrl][1][Abstract/FREE Full Text][2] 2. 2.↵1. Copland M, 2. Tait RC, 3. Walker ID . A retrospective follow-up study of oral anticoagulant control and haemorrhagic complications in an elderly population with atrial fibrillation. Br J Haematol 2000;08(S1): 56. [OpenUrl][3] 3. 3.↵1. Connolly SJ . Anticoagulation for patients with atrial fibrillation and risk factors for stroke. BMJ 2000;320:1219–1220. (6 May.) [OpenUrl][4][FREE Full Text][5] # Cohort was younger than many patients with atrial fibrillation in primary care {#article-title-6} EDITOR—Kalra et al's paper extends our knowledge of how effectively research into stroke prevention in atrial fibrillation can translate into clinical practice.1 However, the authors studied patients recruited in district general hospitals and whose anticoagulants were controlled in hospital outpatient clinics. As a result the patients differed greatly from the whole population of patients with atrial fibrillation. The cohort studied was considerably older than that in the pooled atrial fibrillation … [1]: {openurl}?query=rft.jtitle%253DBMJ%26rft.stitle%253DBMJ%26rft.issn%253D0007-1447%26rft.aulast%253DKalra%26rft.auinit1%253DL.%26rft.volume%253D320%26rft.issue%253D7244%26rft.spage%253D1236%26rft.epage%253D1239%26rft.atitle%253DProspective%2Bcohort%2Bstudy%2Bto%2Bdetermine%2Bif%2Btrial%2Befficacy%2Bof%2Banticoagulation%2Bfor%2Bstroke%2Bprevention%2Bin%2Batrial%2Bfibrillation%2Btranslates%2Binto%2Bclinical%2Beffectiveness%26rft_id%253Dinfo%253Adoi%252F10.1136%252Fbmj.320.7244.1236%26rft_id%253Dinfo%253Apmid%252F10797031%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [2]: /lookup/ijlink?linkType=ABST&journalCode=bmj&resid=320/7244/1236&atom=%2Fbmj%2F321%2F7269%2F1156.atom [3]: {openurl}?query=rft.jtitle%253DBr%2BJ%2BHaematol%26rft.volume%253D08%26rft.spage%253D56%26rft.atitle%253DA%2BRETROSPECTIVE%2BFOLLOW-UP%2BSTUDY%2BOF%2BORAL%2BANTICOAGULANT%2BCONTROL%2BAND%2BHAEMORRHAGIC%2BCOMPLICATIONS%2BIN%2BAN%2BELDERLY%2BPOPULATION%2BWITH%2BATRIAL%2BFIBRILLATION.%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [4]: {openurl}?query=rft.jtitle%253DBMJ%26rft.stitle%253DBMJ%26rft.issn%253D0007-1447%26rft.aulast%253DConnolly%26rft.auinit1%253DS.%2BJ%26rft.volume%253D320%26rft.issue%253D7244%26rft.spage%253D1219%26rft.epage%253D1220%26rft.atitle%253DAnticoagulation%2Bfor%2Bpatients%2Bwith%2Batrial%2Bfibrillation%2Band%2Brisk%2Bfactors%2Bfor%2Bstroke%26rft_id%253Dinfo%253Adoi%252F10.1136%252Fbmj.320.7244.1219%26rft_id%253Dinfo%253Apmid%252F10797015%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [5]: /lookup/ijlink?linkType=FULL&journalCode=bmj&resid=320/7244/1219&atom=%2Fbmj%2F321%2F7269%2F1156.atom